沼氣衛(wèi)生系統(tǒng)

1、Biogas Sanitation Systems Heinz-Peter MANG & Ina Patricia JURGAInstitute of Energy and Environmental Protection (IEEP)Chinese Academy of Agricultural Engineering (CAAE)E-mail: International Conference on123Basic ideas of Ecological Home and Prosperity ProgramBasic ProjectPROGRAMImproved stove, energ

2、y saving “Kang”Biogas digesterNorthern “Four-in-one”Solar cooker, water heater, heating houseWind power, Photovoltaic, micro hydroRoad, water supply infra. reconstruction Southern “Pig-biogas-fruit”Northwest “Five-Matches”Biogas digester,animal-pen, kitchen, toilet reconstructionsCore ProjectExtensi

3、on Project4All organic materials can ferment or be digested:faeces from cattle, pigs and possibly from poultry and humans, organic waste, energy crops, and organically loaded wastewater. 5If the daily amount of available dung (fresh weight) is known, gas production per day will approximately corresp

4、ond to the following average values: 1 kg cattle dung 40 litre biogas 1 kg buffalo dung 30 litre biogas 1 kg pig dung 60 litre biogas 1 kg chicken droppings 70 litre biogas 1 kg human excrements 60 litres biogas If the live weight of all animals whose dung is put into the biogas plant is known, the

5、daily gas production will correspond approximately to the following values: cattle, buffalo and chicken: 1,5 litres biogas per day per 1 kg live weightBiogas potentialDiets higher in protein and lower in fibre, resulting in higher biogas production values! The maximum of biogas production from a giv

6、en amount of raw material depends on the type of substrate. As more biogas per unit produced, as better the BOD reduction.6biogas as energy1 m3 Biogas (approx. 6 kWh/m3) is equivalent to: Diesel, Kerosene (approx. 12 kWh/kg) 0.5 kg Wood (approx. 4.5 kWh/kg) 1.3 kg Cow dung (approx. 5 kWh/kg dry matt

7、er) 1.2 kg Plant residues (approx. 4.5 kWh/kg d.m.) 1.3 kg Hard coal (approx. 8.5 kWh/kg) 0.7 kg City gas (approx. 5.3 kWh/m3) 1.1 m3 Propane (approx. 25 kWh/m3) 0.24 m3Amount cookedTime (min)Gas(L) 1 L water10405 L water35165500 g rice301401000 g rice37175350 g pulses60270700 g pulses70315Equipment

8、Amount of biogasHousehold burners200 450 L/hIndustrial burners1000 3000 L/hRefrigerator 100 L depending on outside temperature30 75 L/hGas lamp, equiv. to 60 W bulb120 150 L/hBiogas/biodiesel engine per bhp420 L/hGeneration 1kwh electricity biogas/biodiesel or gas engines500-700 L/hSasse, India, 198

9、87Options for biogas utilisation8Biogas as fuel for waste incinerationWaste incineration needs fossil fuel to burn waste in a rotating kiln; this could be partially replaced by biogas9Electricity from CHP-enginesGas-engine electricity generation needs medium-grade biogas purification (removal of moi

10、sture and trace gases) 10Biogas feed in the natural gas gridBiogas needs to be high-graded with carbon-dioxide removal to natural gas standards.11Biogas as fuel for vehiclesThis option needs high-upgraded biogas with a quality compared to LNG/CNG12For biogas plant regarded from an energy point of vi

11、ew, its better to have some animal manure or additional feed of organic waste, and to optimize the retention time related to energy output ./. construction volume.For biogas as a sanitation option it is more important to look for the sanitization of the incoming black-, brown-, or wastewater and org

12、anic wastes. Therefore the input material stays longer in the digester, and the retention time will be adopted with an optimum of sanitation degree and biogas production. Biogas sanitationHuman excreta from dry or low flush toilets and biodegradable organic fraction of household waste could enter a

13、(on-site or off-site) anaerobic (wet or dry) digester to be treated and to produce biogas. 13 Under plug flow conditions - without post-treatment in wetlands or polishing ponds - the usual treatment of faecal sludge, properly applied by Retention timeanaerobic psyrophilic fermentation (above 10C and

14、 retention times of at least 100 days),mesophile digestion (above 30C with retention times of at least 50 days) or thermophile digestion temperature (above 55C and about 10 days retention time), can be considered as sufficient. (volume ratio: 10:5:1)14The concentration of nitrogen in the black water

15、 cold be so high, that the digestion process could be stopped. Ammonia from the urine will be transformed by enzymes in urea, carbon dioxide and ammoniac. Urea will be toxic to the bacteria (self-intoxification).This could be solved by solid/liquid separation (AQUATRON, filter bag, settler) or urine

16、 diversion toilet bowls and pans, and the “solid” part (faeces, sludge) are digested. Biogas from brown water15Benefits Achievable Social benefitsEconomic benefitsEnvironment and ecological16Social BenefitsJob creation for local peopleHealth improvementdisease reduction due to utilization of clean e

17、nergy and end products use as land fertilizerEspecially good for womenLifestyle improvement17Dispose of your waste water and save money doing it!SRC upbeat about biodigester septic tank technologyBy Petre Williams Observer staff reporterSunday, May 02, 2004In the 1970s when the Germans introduced bi

18、odigester septic tank (BST) technology - a money- saving way to solve the acute waste water disposal practices in Jamaica - it was an idea whose time had not yet come.Three decades later, the state-run Scientific Research Council (SRC) is getting ready to embark on an aggressive promotion of its bio

19、digester septic tank system, hoping to cash in on the many spin-off benefits. SRC executive director, Dr Audia Barnett, is enthusiastic about the technology: You are treating your waste water. You are getting gas, which you can use for cooking. You are getting water you can use for irrigation and yo

20、u are getting literally no waste, she told the Sunday Observer.Theres practically no (need for) maintenance. Its a system that my staff likes to call set it and forget it. Its not like the septic tank that you have to be pumping every now and again, Barnett said.The SRC is reporting that there has b

21、een renewed interest in BSTs, as they are called. We have seen a resurgence. of interest in our BSTs, both at the residential level and at the industrial level, said Barnett.18Economic Benefitsenergy savingBiogas lamp1920Biofuels and conversion% dry matterGas prod.Combust.Manure7 - 12+ + +-Black (br

22、own) water0.5 - 2+- - -Sludge25 - 50+ + / -Slaughter waste40 - 60+ + + + + / - -Wet organic waste20 - 50+ / -+ / -Energy in brown water per person per year75 200 kWh net, biogas energy outputGTZ, 1997 and NLH, 2003Diets higher in protein and lower in fibre, resulting in higher biogas production valu

23、es! 21改廚Avoid indoor air pollution22Anaerobic sanitization (BRTC, China 1985)23Reduction of pathogens24Smell reduction through digestion25Economic BenefitsEnergy savingFarm developmentVarious use of end product26Model Pure benefit yearly(unit: yuan)Household biogas600Northern “four-in-one” 3000South

24、ern“pig-biogas-fruit”2000Economic benefits-income increase27LivestockBiodigestorPondCrops, trees, shrubsManureEffluentIrrigationFeedFamilyBiogasExcretaThe ecological farm28Pig-pen improvement29303.5mu forest8 mOne biogas digester3Environmental and ecological protect forest31The use of biomass as a s

25、ubstitute for fossil fuel represents a high potential for the avoidance of GHG emissions. One opportunity is associated with the processing of faeces or brown water, by which means biogas is obtained. The latter produces energy and at the same time reduces tradable methane emissions1.Fossil energy s

26、ubstitution1) The Clean Development Mechanism (CDM) is a compensation mechanism. It allows industrial countries to obtain emission reduction credits with emission reduction projects in developing countries. The credits are called Certified Emission Reductions (CER). An Annex I country invests in a N

27、on-Annex I Country and cooperates with private or public institutions. The accounting of such reduction credits starts retroactively from the year 2000 onward. 32Environmental benefits-CO2 and CH4 reduction CO2CH4CH433Composting of feaces and biowaste is ambivalent. Composting (aerobic storage) of f

28、eaces can reduce CH4 emissions but will increase N2O by a factor of 10. In CO2 equivalents there is no change. Composting is not recommended as a Climate Emission Gas mitigation option (Bates 2001)1. Controlled anaerobic digestion of feaces, manure and biowaste combined with biogas production is a m

29、ost promising option for GHG mitigation (Jarvis & Pain 1994)2. Bates J (2001): Economic Evaluation of Emission Reductions of Nitrous Oxides and Methane in Agriculture in the EU. Contribution to a Study for DG Environment, European Commission by Ecosys Energy and Environment, AEA Technology Environme

30、nt and National Technical University of Athens. Jarvis SC and Pain BF (1994): Gaseous emissions from an intensive dairy farming system. Proceedings of the IPCC AFOS Workshop. 55-59. Canberra, Australia.No GHG mitigation by composting!34Biogas for overall household sanitation decentralised treatment

31、of household wastewater with or without agricultural and organic household , kitchen wastevaluable nitrogen remains availableenergyfertilizer35Baffled septic tank137,000 community biogas septic tanks (DEWATS) for purification of household wastewater with more than 0.5 billion tons of wastewater treated annually.36Zusammensetzung FkalschlammTechnical Concept Biogas tankSludge stabilization and separation tank Oct. 2005 Andreas Schmidt37Sketch of b